Selection and characterization of Beauveria spp. isolates to control the broad mite Polyphagotarsonemus latus (Banks, 1904) (Acari: Tarsonemidae)

Seleção e caracterização de isolados do fungo Beauveria spp. visando ao controle do ácaro branco Polyphagotarsonemus latus (Banks, 1904) (Acari: Tarsonemidae)

Abstract

This study was performed under laboratory conditions to identify isolates of the fungus Beauveria spp. that can control Polyphagotarsonemus latus in the greenhouse and field. Thirty Beauveria spp. isolates were tested by spraying 1 mL conidia (1 × 10⁸ conidia/mL) on pepper leaf discs containing 15 mites. Evaluations were performed on the 3rd and 6th day post application by counting the number of dead mites. Vegetative growth and conidial production were measured from the selected isolates, and bioassays were conducted in the greenhouse on bean seedlings in plastic pots. The isolate Unioeste 53 was selected, and a conidial suspension (1 × 10⁸ conidia/mL) was applied with a backpack sprayer. The evaluation consisted of pre- and post-treatment counts of the number of live mites on ten leaflets in both the plots treated with the fungus and control plots, and the same procedure was followed for the field experiment. In the laboratory, the Unioeste 53 isolate resulted in total and confirmed mortality rates of 70% and 57.7%, respectively. In the greenhouse, the population decreased by 76.71% by the 16th day after application. In the field, the population decreased by 66% by the 12th day after application, demonstrating the potential of this fungus for mite management.

Keywords:
microbial control; entomopathogenic fungi; broad mite